Audio amplifier with DSP

programmista123 · Joined: 31 Jan 2018 Posts: 141

Hello,

I received enclosures today. Approximately 60-70% SW is done.

Regards,
Przemek

programmista123 · Joined: 31 Jan 2018 Posts: 141

Hello,

Just before end of the year I can say - project is DONE Very Happy

What was changed in compare to previous post? Enclosure and front.

It is supporting 3 inputs: AUX, SPDIF optical and coax. Sample rate up to 48 kHz.
During normal operation we have only information about source, volume and Mute status.

Each channel can be trimmed to custom volume (sub-menu).

Each amplifier can be programmed by any of DSP program (1-14) (sub-menu).

How it works?
Each amplifier need a DSP program. It need to be done by Merus Audio Amplifier Configuration. It can work with connected amps and without however the 1st option is the case when real-time audio response measurements are required.

When configuration is done .csv file with DSP data is present. Some excel work, copy to HxD, save as .hex and EEPROMs can be programmed. I have 2 EEPROMs and each of them can store 7 different configuration. CRC16 is implemented. In case of wrong program's CRC - amplifier receiver (I2S) is off.
Example from picture above (DSP Route).
Route 2: to the first amplifier we are sending DSP program no. 1, to second amplifier - program no.0 which is "amp off". To the third amplifier, program no. 3. Routing it is full flexible.

During normal operation in my room (all amps were ON) I never saw temperatures higher than 35 deg.C. Fan is set for 70 deg.C.

As you can see, it can be a bit complicated for the uninitiated Very Happy

I'll share with you some audio performance measurements when done.

All the best,
Przemek

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

hi Przemek

thanks for the update. well done !
yes to me it seems like a lot of work to get audio. but i also know that it is part of the fun to get it done complete as you want it.
oled looks great. only seems first line is off by a space. (trips my ocd Smile

)

that was a time when man had only tools, car, and his audio. pre amps, amps, equalizers, boxes , pick up, cassette , a whole tower. my dad spend a lot of time with it.
the audio they make nowadays does not compare to even the simplest radio (tuner with amp). but it could be hearing too Smile

anyway, good to see that custom audio is still alive Very Happy

if you need an eeprom programmer/eraser i still have one that i will not use anymore.

programmista123 · Joined: 31 Jan 2018 Posts: 141

Hello,

Thanks Mark! You're right. A lot of things need to be done to get audio from speakers Very Happy

OLED - correct, it was intended.

Regarding custom audio... . According to Infineon webpage, these chips received status: not for new design few weeks ago. My engineering heart broke Razz

What is interesting in new PC SW which was published 2nd January this year, MA2306 was added. It looks like output power is higher however it will no go to mass production. Business is business.
Probably I'll buy some MA2304DNS to have them on the stock.

I'm sharing additional photo - 3 way column with real time tuning (Dayton Audio OmniMic V2) Wink

All the best,
Przemek

albertsm · Joined: 09 Apr 2004 Posts: 5922 Location: Holland

it looks great !
yes when status changes into 'not active' it is a problem. today i was looking up parts and many have long delivery times. others do not exist anymore.
i usually get an email from the supplier when something changes. that at least gives the change to get some stock.
most pcb i produce originated from long time ago and they still can be produced, some times with some challenges. but atmel/microchip is a reliable source.

recently i looked into DSP. There are many chips and platforms and probably lot of software too. i still need to do a crash course when i have some time.